The present invention relates to a water closet (abbreviated to W.C. hereinafter in this specification) flushing apparatus and more particularly to a W.C. flushing apparatus capable of efficiently charging flushing water not only to a W.C. bowl but also to a trap discharge passage which is disposed in the vicinity of the bottom of the W.C. bowl and which can produce the siphon action.
A W.C. comprises a bowl which receives waste matter from the human body and a trap discharge passage substantially in the form of an inverted U and communicated with the bottom of the W.C. bowl.
In order that the trap discharge passage may produce the siphon action which is required for not only decreasing the quantity of flushing water charged into the W.C. bowl but also positively causing the discharge of fluid waste together with the flushing water, there has recently been proposed a method in which flushing water is fed through independent flushing water lines to the W.C. bowl and the trap discharge passage.
For instance, in the case of the W.C. flushing apparatus disclosed in Japanese Patent Publication No. 30092/1980, an independent flushing water pipe and a flushing water discharge line are communicated with a W.C. bowl and a trap discharge passage, respectively, thereby charging flushing water to them independently of each other. In the W.C. flushing apparatus of the type just described above, solenoid controlled valves are inserted into the flushing water pipe and the flushing water charging line, respectively and are closed or opened in response to the signal transmitted from a timer. Furthermore, a port for charging flushing water into the trap discharge passage is opened in the vicinity of the trap discharge passage.
In the W.C. flushing apparatus of the type just described above, the solenoid controlled valves are so controlled that first flushing water is charged into the trap discharge passage to produce the siphon action, whereby waste matter and flushing water are discharged. Thereafter flushing water is charged into the W.C. bowl to clean the same. Therefore as compared with the conventional W.C. flushing apparatus of the type in which flushing water is charged only into the W.C. bowl, the effect for causing the trap discharge pipe to function as a siphon requiring little flushing water so that flushing water can be saved, can be attained.
However, in the case of the conventional flushing apparatus of the type described above, the solenoid controlled valves are controlled to open or close in response to a time interval set by the timer so that there is the problem that when the pressure of the flushing water in the flushing water charging line is varied, the flow rate is also varied so that an effective flushing effect cannot be attained. In particular, there exists the problem that when the pressure of the flushing water drops, waste matter remains in the W.C. bowl.
The port for charging flushing water into the trap discharge passage is opened when the W.C. bowl is molded and is not adapted to charging flushing water as a jet stream. Therefore there exists the problem that the quantity of flushing water used to cause the trap discharge passage to act as a siphon is not decreased as expected.
Furthermore, cleaning of the W.C. bowl with flushing water is carried out after the discharge of waste matter so that there exists the problem that waste matter which was not completely discharged by the siphon action of the trap discharge passage again remains in the W.C. bowl.
In order to overcome the problems encountered in the above described W.C. flushing apparatuses, a W.C. flushing apparatus as disclosed in Japanese Patent Publication No. 42057/1986 has been proposed. With this W.C. flushing apparatus, in order to solve the problem that the quantity of flushing water varies in response to variations in the pressure of the flushing water, a flushing water storage tank for previously storing the flushing therein is provided. The inner space of the flushing water storage tank is divided into a flushing water charging line for charging the flushing water into the trap discharge passage and a flushing water charging line for charging the flushing water into the bowl. That is, a predetermined quantity of flushing water once stored in the storage tank is distributed in the storage tank and is charged.
When such flushing water storage tank is provided, the problem of an insufficient quantity of charged water due to the variations in the pressure of flushing water can be solved. However, in order to provide such a storage tank, more space and installation work are required. Moreover, there exists the problem that the construction of the flushing water storage tank is complicated so that the cost of manufacture is expensive.
A further problem of the conventional W.C. flushing apparatus of the type described above resides in the fact the flushing operation cannot be carried out until a surface level of flushing water in the storage tank reaches a predetermined level, and therefore the W.C. flushing apparatus cannot be continuously used.
In the W.C. flushing apparatus of the type described above, the flushing water charging process is so determined that flushing water is first charged into the trap discharge passage so as to produce the siphon action and then the flushing water is charged into the W.C. bowl to clean it. As a result, when the W.C. bowl is extremely contaminated, there arises the problem that the W.C. bowl cannot be satisfactorily cleaned.
In addition, since the cross sectional area of the port for charging flushing water into the trap discharge passage is large, the kinetic energy of flushing water discharged through the port is reduced so that the effect of the flushing water jet is not satisfactory. As a result, there arises the problem that the quantity of flushing water to be charged to the trap discharge passage to produce the siphon action cannot be increased sufficiently within a short period of time so that the quantity of flushing water charged through the port cannot be sufficiently decreased.